Implantable cross-pin for anterior cruciate ligament repair

ABSTRACT

A novel cross-pin for use in ACL reconstructive surgical procedures. The cross-pin has an elongated body having a distal tapered end. A guide wire opening in the distal end is in communication with a tunnel contained in the distal end. There is a trough extending into the outer surface of the trough for receiving a guide wire. The trough is in communication with the tunnel.

TECHNICAL FIELD

The technical field to which this invention relates is orthopedicimplants, in particular, orthopedic implants useful for anteriorcruciate ligament repair procedures.

BACKGROUND OF THE INVENTION

The anterior cruciate ligament (ACL) is a major component of the softtissue in a human knee that is responsible for stability of the knee. Inaddition to the ACL, several other ligaments provide stability includingthe posterior cruciate ligament (PCL) and the medial and lateralcollateral ligaments (MCL/LCL). It is not uncommon for a person torupture or tear the ACL during various types of physical activitiesincluding sports, work, and the like. The tear or rupture can be causedby trauma such as impact, or by abrupt stopping or turning movementswhich cause exceptional forces to be transmitted to the ACL. Typically atorn or ruptured ACL cannot be repaired using conventional soft tissuerepair procedures such as suturing, stapling, etc. It is necessary toreplace the ACL with a graft. The graft may be an autograph harvested,for example, from the patient's patellar tendon or hamstring tendon, anallograft harvested from a cadaver, a xenograft, or an artificialman-made tendon. Tissue-engineered ligaments may also be available. In atypical ACL reconstruction, axial tunnels are drilled into the patient'stibia and femur by the surgeon using conventional surgical drills, drillguides and instruments. Once the knee is prepared, the graft is theninserted by the surgeon into the tibial and femoral tunnels, such thatone end of the graft resides in each tunnel. The graft is adjusted bythe surgeon to provide the desired range of motion. Finally, the graftis secured at both ends in a conventional manner to complete the ACLrepair or reconstruction. For example, the graft ends may be securedwith conventional interference screws, etc. An alternate method ofsecurement is to use a cross-pin, in particular a femoral cross-pin. Inthis type of procedure, a transverse hole is drilled into the end offemur such that it intersects the femoral tunnel, and a guide wire isthreaded through the transverse tunnel. A cannulated cross-pin is theninserted into the transverse tunnel over the guide wire and underneath alooped end of the graft in order to secure the graft in the femoraltunnel. The guide wire is then removed. If desired, the other end of thegraft may be secured in the tibial tunnel by a tibial cross-pin in asimilar manner.

Although the cannulated cross-pins known in this art are sufficient andadequate for their intended purposes, there is a continuing need in thisart for improved cross-pins and surgical techniques. For example, thereis a need for novel cross-pins that provide uni-cortical fixation andintraoperative removal or revision, eliminate or reduce the need formultiple size (length) implants, and simplify the need to makemeasurements and calculations in order to determine appropriate length.

Accordingly, there is a need in this art for novel cannulated cross-pinsfor use in ACL reconstruction procedures.

SUMMARY OF THE INVENTION

A novel cross-pin for use in ACL reconstruction procedures is disclosed.The cross-pin has an elongated member having a proximal end, a distalend, an outer surface, and a longitudinal axis. A nose member extendsout from the distal end. The nose member has a proximal end and a distalend. There is an axial trough in the member extending through the outersurface. The trough has a proximal end, a distal end, a bottom, an opentop and a passageway. There is a guide-wire opening in the distal end ofthe nose member. There is also an interior passage in the nose memberthat extends from the guide-wire opening through to the trough such thatthe passage is in communication with the guide wire opening and thetrough.

Another aspect of the present invention is a method of securing the endof an ACL ligament implant in a bone tunnel using the above-describedimplantable cross-pin.

These and other aspects and characteristics of the present inventionwill become more apparent from the following description andaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the cross-pin of the present invention.

FIG. 2 is a top view of the cross-pin of FIG. 1.

FIG. 3 is a partial cross-section of a knee illustrating a cross-sectionof the bottom of a femur in the knee having a femoral tunnel with atransverse tunnel; a cannula sleeve is illustrated in the transversetunnel along with a trocar/drill used to drill the transverse tunnel andemplace the cannula sleeve. Also illustrated is a cross-section of thetop of a tibia in the knee having a tibial tunnel.

FIG. 4 illustrates the femur of the knee of FIG. 3 after the transversetunnel has been drilled and the trocar/drill has been removed, andfurther illustrates a flexible guide wire member threaded through thetransverse tunnel and the femoral tunnel; a partial cut-away view of theupper end of a looped ligament graft is shown emplaced in the femoraltunnel.

FIG. 5 illustrates a cross-pin of the present invention threaded ontothe guide wire extending through a transverse tunnel in a femur.

FIG. 6 illustrates an insertion rod threaded onto the guide wire and incontact with the proximal end of the cross-pin immediately prior toemplacement in the transverse tunnel.

FIG. 7 illustrates the cross-pin of the present invention threaded overa guide wire and implanted in the transverse tunnel such that thecross-pin is beneath the top of an ACL graft; fixation of the lower endof the graft in the tibial tunnel is not illustrated.

DETAILED DESCRIPTION OF THE INVENTION

The cross-pins of the present invention can be made from a variety ofconventional biocompatible materials useful in implants. The materialsmay be absorbable or non-absorbable. Examples of conventionalnon-absorbable materials include surgical stainless steel, nickeltitanium alloys, ceramics, Delrin, polyethylene, and othernon-absorbable polymers including, but not limited to, polypropylene,and Acetal. Examples of bioabsorbable materials include PLA, PGA,polydioxanone, polycaprolactone, copolymers thereof, and the like. Theterm “natural polymer” refers to polymers that are naturally occurring,as opposed to synthetic polymers. In embodiments where the deviceincludes at least one synthetic polymer, suitable biocompatiblesynthetic polymers can include polymers selected from the groupconsisting of aliphatic polyesters, poly(amino acids),copoly(etheresters), polyalkylenes oxalaes, polyamides, tyrosine derivedpolycarbonates, poly(iminocarbonates), polyorthoesters, polyoxaesters,polyamidoesters, polyoxaesters containing amine groups,poly(anhydrides), polyphosphazenes, polyurethanes, poly(etherurethanes), poly(ester urethane) and blends thereof. Suitable syntheticpolymers for use in the present invention can also include biosyntheticpolymers based on sequences found in collagen, elastin, thrombin,fibronectin, starches, poly(amino acid), poly(propylene fumarate),geletin, alginate, pectin, fibrin, oxidized cellulose, chitin, chitosan,tropoelastin, hyaluronic acid, ribonucleic acids, deoxyribonucleicacids, polypeptides, proteins, polysaccharides, polynucleotides andcombination thereof. The devices of the present invention may also bemanufactured from conventional biocompatible natural polymers. Ifdesired, the bioabsorbable materials may contain osteoinductive orosteoconductive materials, polymers and blends of polymers including butnot limited to calcium hydroxyapatite, tricalcium phosphate, and thelike.

The cross-pins of the present invention may be made using a variety ofconventional manufacturing processes including machining, molding, etc.,and combinations thereof.

As seen in FIG. 1, a cross-pin 5 of the present invention has anelongated member 10. The member 10 has proximal end 20 and distal end40. The member 10 is seen to have a longitudinal axis 11. Extending fromthe distal end 40 is the nose member 50 having proximal end 55 anddistal end 60. Member 50 may have a variety of geometric configurationsincluding tapered, conical, frustoconical, bullet-shaped, rounded,stepped, etc., and combinations thereof. Extending into the outersurface 15 of the member 10 is the axial trough 70. Trough 70 is seen tohave open proximal end 72, distal end 74, bottom 75, opposed sides 77.Trough 70 may have a variety of cross-sections, including U-shaped,circular, arcuate, square, rectangular, etc. and combinations thereof.Trough 70 is also seen to have open top 79 extending through surface 15.The trough 70 also has passage 80. The nose member 50 is seen to have aguide wire opening 62 at its distal end 55, which is preferably locatedconcentrically about the longitudinal axis 11. Nose end member 50 isseen to contain a tunnel 100 extending through to trough 70. Tunnel 100is seen to have passage 102 that is in communication with the guide wireopening 62 in the nose end member 50 and also in communication with thetrough passage 80 at distal end 74.

The cross-pin of the present is used in combination with a conventionalguide wire in order to secure an ACL replacement ligament graft into afemoral tunnel. A variety of methods of securing ACL replacementligament grafts in femoral tunnels using conventional cannulatedcross-pins are known in the art. For example U.S. patent applicationSer. No. 10/439,752, which is incorporated by reference, discloses amethod of moving an ACL graft into a femoral tunnel and securing it witha cannulated cross-pin moved over a guide wire.

A method of using the novel cross-pins of the present invention tosecure the end of a graft in a bone tunnel is now described. Referringto now to FIGS. 3-7, the novel cross-pin 5 of the present invention isseen used to secure an ACL graft 200 in a femoral bone tunnel 190contained in a femur 180 of a knee 150. Typically in such a procedure, apatient is prepared by the orthopedic surgeon in a conventional mannerby immobilizing the patient's knee 150 in a desired configuration. Then,in a conventional manner longitudinal or axial bone tunnels are drilledin the ends of the tibia 170 and the femur 180 adjacent to patient'sknee 150 (See FIG. 3). The tibial tunnel 175 and the femoral tunnel 190are seen to be in substantial alignment. In addition, a transversetunnel 270 is drilled into the femur 190 such that the traverse tunnel270 intersects the femoral tunnel 190 toward the top 198 of the femoraltunnel 190. This can be done in a variety of conventional manners. Forexample as seen in FIG. 3, a conventional trocar drill member 210 isaffixed with a pin 211 in a conventional cannula sleeve 220. The trocardrill member 210 has pointed distal end 212 and flat proximal end 215.Cannula sleeve 220 has proximal end 222, distal end 225 and passage way227. The proximal end 215 is mounted to a conventional surgical drilland the distal end 212 drills through the femur 180 to create thetransverse tunnel 270, while emplacing at least a portion of the distalend 225 of cannula sleeve 220 therein. Other conventional methods ofdrilling the transverse tunnel and emplacing the cannula sleeve 220 maybe used as well. Transverse tunnel 270 has opposed open ends 272 and273, and passage 275. After the trocar or drill has been removed fromtunnel 270, an ACL replacement graft 160 is moved into the femoraltunnel 190 in a conventional manner, for example, by attaching tosutures that are pulled through suture tunnel extension 197. Aconventional guide wire 120 is threaded through the transverse tunnel270 through such that a portion of the guide wire 120 is beneath the top168 of the upper end 166 of the looped ACL graft 160. Conventionaltechniques and equivalents thereof may be used to thread the guide wire120 and move the graft 160 into place. Guide wires used in this art areconventionally known and may be made of a variety of biocompatiblematerials including surgical stainless steel, Nylon, Nitinol, etc.Initially, the cross-pin 5 is threaded onto a guide wire 120 byinserting a first end 122 of the guide wire 120 into the guide wireopening 62 in nose member 55 and threading the guide wire 120 throughthe tunnel 100 out of passage 102 and into passage 80 of the trough 70 .The end 122 of the guide wire 120 exits the proximal end 72 of thetrough 70 through an opening 22 in the proximal end 20 of the cross-pin5. The guide wire 120 is then threaded through the insertion instrument300. The instrument 300 is seen to have a proximal handle 305 and anelongated member 310 having a distal end 315. The insertion instrument300 has a lumen or longitudinal passage 302 running the length of theinstrument. The instrument 300 is seen to have set screw 306 havingdistal end 307 that is moveable into passage 302 in handle 305 tooptionally engage guide wire 120. The distal end 315 of instrument 300is located to engage the proximal end 20 of cross-pin 5. Then, thecross-pin 5 of the present is moved by the insertion tool 300 (viapushing, hammering, etc.) through the cannula sleeve and into tunnel 270such that it is positioned in the femoral tunnel 190 underneath the top166 of ACL graft 160 in the transverse tunnel 270 and upper femoraltunnel 198. Optionally, the insertion instrument is maintained in afixed position relative to the guide wire 120 by the set screw 306,although it may also be slid along the wire 120. This implantation ofthe cross-pin 5 secures the end 166 of the ACL graft 160 in the femoraltunnel 190. The guide wire 120 is then removed along with the cannulasleeve 220 and this portion of the surgical procedure is completed. Theother end 162 of ACL graft is secured in the tibial tunnel 175 usingconventional securing procedures and techniques such as the use ofinterference screws or cross-pins (not shown). This then completes thesurgical procedure and the reconstruction of the knee 150 with the ACLgraft 160 secured in place. Although not shown, a knot may be placed inthe guide wire 120 distal to the nose member 50. The knot will have anoverall dimension larger than the maximum dimension of the guide wireopening 62. Then, if the surgeon desires to remove the cross-pin 5 afteremplacement in transverse tunnel 270 for any reason during any stage ofthe procedure, the surgeon pulls proximally on the guidewire 120 toback-out and remove the cross-pin 5.

The novel method and cross-pin 5 of the present invention have manyadvantages. The advantages include the ability to remove pin at time ofsurgery, and, no uni-cortical fixation (equal distribution of loadacross the device). In addition the pin is centered in the femoraltunnel and a single size implant may be used.

Although this invention has been shown and described with respect todetailed embodiments thereof, it will be understood by those skilled inthe art that various changes in form and detail thereof may be madewithout departing from the spirit and scope of the claimed invention.

1. An implantable cross-pin, comprising: an elongated member having aproximal end, a distal end, a longitudinal axis, and an outer surface; anose member extending out from the distal end said elongated memberhaving a proximal end and a distal end; an axial trough in the elongatedmember extending though the outer surface, said trough having a proximalend, a distal end, a bottom, opposed ends, an open top and a passageway;a guide wire opening in the distal end of the nose member; and, aninterior passage in the nose member extending from the guide wireopening and extending into the trough such that the passage is incommunication with the guide wire opening and the trough.
 2. Thecross-pin of claim 1, wherein the cross-pin comprises a biocompatiblematerial.
 3. The cross-pin of claim 2, wherein the material isbioabsorbable.
 4. The cross-pin of claim 2 wherein the material isnon-absorbable.
 5. The cross-pin of claim 3, wherein the bioabsorbablematerial is selected from the group consisting of PLA, PGA, andcopolymers thereof.
 6. The cross-pin of claim 4, wherein thenon-absorbable material is selected from the group consisting ofsurgical stainless steel, nickel titanium alloys, ceramics, Delrin,polyethylene, polypropylene, acetal, and ceramics.
 7. The cross-pin ofclaim 1, wherein the proximal end of the cross-pin comprises an openingin communication with the proximal end of the trough.
 8. The cross-pinof claim 1, wherein the guide wire opening is concentric with thelongitudinal axis.
 9. The cross-pin of claim 1, wherein the nose memberhas a bullet shape.
 10. The cross pin of claim 1, wherein the nosemember has a frustoconical shape.
 11. The cross-pin of claim 1, whereinthe nose member has a conical shape.
 12. A method of securing an end ofan ACL ligament implant in a bone tunnel, comprising; I. providing aimplantable cross-pin, said cross-pin comprising: an elongated memberhaving a proximal end, a distal end, a longitudinal axis, and an outersurface; a nose member extending out from the distal end, saidfrustoconical nose member having a proximal end and a distal end; anaxial trough in the member extending though the outer surface, saidtrough having a proximal end, a distal end, a bottom, opposed ends, anopen top and a passageway; a guide wire opening in the distal end of thenose member, said guide wire opening having a maximum dimension; and, aninterior passage in the nose member extending from the guide wireopening and extending into the trough such that the passage is incommunication with the guide wire opening and the trough. II. drillingan axial, femoral tunnel in a femur; III. drilling a transverse tunnelin the femur, said transverse tunnel intersecting the femoral tunnel;IV. placing a guide wire through the transverse tunnel such that opposedends of the guide wire extend out through opposed end of the transversetunnel, and such that the guide wire is beneath the end of the ACLimplant; V. moving an end of an ACL implant into the femoral tunnel; VI.threading the cross-pin onto the guide wire such that the wire entersthe guide wire opening, and is partially contained within the interiorpassage and the trough passage way; and, VII. moving the cross-pin overthe guide wire to implant the cross-pin in the transverse tunnel, underthe end of the ACL implant.
 13. The method of claim 12 comprising theadditional step of tying a knot in the guide wire distal to the nosemember, wherein the knot has a maximum outer dimension, wherein theouter dimension of the knot is greater than the maximum dimension of theguide wire opening of the nose member.
 14. The method of claim 12additionally comprising the steps of providing an insertion toolcomprising an elongated member having a proximal end and a distal end, ahandle attached to the distal end and a passageway through the insertiontool, and, threading the guide wire through the passage on the insertiontool such that the distal end of the insertion tool contacts theproximal end of the cross-pin.
 15. The method of claim 14 wherein theinsertion tool comprises a set screw mounted thereto such that the setscrew extends at least in part into the passageway of the insertiontool.
 16. The method of claim 15 additionally comprising the step ofengaging the guidewire with the set screw such that the insertion toolmoves with the guide wire.